I live less than a mile away from the Kissena Park Velodrome and started watching the races organized by the Kissena Bike Club a few years ago. The season starts this Sunday, May 1st and races are scheduled for just about every night through all of May. (http://www.kissena.info).
Races are held on Wednesday evenings through Labor Day plus other nights as scheduled. One of the more fun events are the messenger races, which last year were held on Thursday evenings. The bike messengers come of out Manhattan and show their track skills. I told them that they should make it more realistic by having folks walk across the track but no one listens to me.
If you live in NYC you should come by to watch a bunch of idiots, I mean really good bikers, going 30mph inches from each other without any brakes.